This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. JP2002-004247, filed Jan. 11, 2002, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a waveform reproduction apparatus and process with which waveform data that have been stored are read out and the waveforms are reproduced.
2. Description of Related Art
For some time, waveform reproduction apparatuses have been known in which waveform data that have been obtained by the sampling of musical tones are stored in a ROM. When a tone generation start indicator is received, the waveform data that have been stored in the ROM are successively read out and musical tones are reproduced. With this kind of waveform reproduction apparatus, a large number of musical tone waveforms are stored in order to obtain good quality musical tones for each kind of timbre covering the entire keyboard range. Another reason for storing a large number of musical tone waveforms is to represent changes in the strength of the tones and the like. There has been a tendency in recent years, together with the expanding transition to higher musical tone sound quality, for increasing the storage capacity for storing the waveform data. Such large capacity storage of the waveform data in a ROM increases the cost of the system. Waveform reproduction apparatuses that are furnished with disk systems such as flexible magnetic disk devices, hard disk devices and the like, have been proposed by Japanese Examined Patent Application Publication (Kokoku) No. Hei 01-001800 and Japanese Patent Publication No. 2671747. However, the access times of these memory devices are comparatively slow.
Embodiments of the present invention provide a waveform reproduction apparatus and process with which a larger amount of musical tone waveform data can be stored on a hard disk and, when the generation of a musical tones has been indicated, for example, by the operation of a keyboard, the musical tone generation is started without delay. It is therefore possible to generate good quality musical tones.
According to embodiments of the present invention, the waveform reproduction apparatus and process of the present invention:
1) Stores the first half portion from the start of the generation of the musical tone waveform up to a specified time in memory that can be read out at a high speed and stores the latter half portion of the waveform in a large-capacity memory such as a hard disk and the like and it is configured such that the latter half portion is read out after the first half portion has been read out. When the read-out of the latter half portion does not occur in time, a specified or pre-determined segment that has been set in the first half portion is read out until the read-out of the latter half portion does occur. By this means, in those cases in which a large volume of waveforms are stored and there has been a start of tone generation by pressing a key and the like, the tone generation can be started immediately. Even in those cases in which the read-out of the latter half portion does not come in time, it is possible to generate the musical tone without errors such as the musical tone being cut off and the like.
2) In addition, a large number of musical tone waveforms are divided into first half portions and latter half portions which are respectively stored on a hard disk. The waveform of the musical tone that has been selected by means of timbre selection and the like is transmitted to the RAM and the musical tone is formed by the waveform data that are read out from the RAM. When the transmission is carried out, first all of the first half portions are transmitted and then the latter half portions are transmitted. By this means, in those cases in which a large number of waveforms are stored and the timbre selection is done and the musical tones for that timbre are generated immediately, it is possible to reduce the time required to put the apparatus in a state in which the tones can be generated.
3) In addition, when all of the first half portions are stored in the high-speed memory and the latter half portions are transmitted from the hard disk to that memory, the latter half portion waveform data that correspond to the tone which is indicated by the key pressing signal and the like are transmitted with priority. By this means, the rapid read-out of the latter half portion of the musical tone for which the tone generation start indicator is received becomes possible and a musical tone having a natural link between the first half portion and the latter half portion can be obtained.
These and other features, and advantages of embodiments of the invention will be apparent to those skilled in the art from the following detailed description of embodiments of the invention, when read with the drawings and appended claims.